The number seven is regarded as special all over the world. Sevens are all around us: days of the week, colors in the spectrum, notes of the scale, and planets in Ptolemaic astronomy. Our lives are sectioned by sevens: seven is the age of reason, at fourteen we reach puberty, at twenty-one we come of age, and later there is a seven-year itch. There are seven directions (up, down, front, back, right, left, and here).
Greek mythology was full of sevens. Apollo’s lyre had seven strings, and his feast day was the seventh of the month. Hercules fetched golden apples from the seven Hesperides, daughters of the West Wind. Thebes had seven gates and seven champions. Niobe had seven sons and seven daughters.
Hebrew lore likewise is heptadic (occurring in groups of seven). Joshua’s army marched around Jericho for seven days, on the last day seven times, with seven priests sounding their ram’s horns. Delilah learned the secret of Samson’s strength on the seventh day of their wedding feast, snipped seven locks from his hair, and bound him with seven cords. Passover and the Feast of Tabernacles are celebrated for seven days. The High Holy Days (Rosh Hashanah and Yom Kippur) are in the seventh Jewish month.
Christianity followed right along. The Lord’s Prayer has seven petitions in it. Mary had seven sorrows, seven joys, and seven glories. Christ spoke seven last words on the cross and appeared after the Resurrection to seven disciples. The Holy Spirit has seven gifts.
Theosophically, seven is very big. Humans, like the cosmos, have seven principles. The major chakras are seven. There are seven rays. Our earth is one of seven globes on which we make seven rounds to evolve through seven kingdoms. Anthropogenesis traces human history through seven races, each with seven subraces. Each of the seven planes of matter has seven subplanes,
Even numerically seven is noteworthy. The lunar month consists of about 28 days, and 28 is the sum of the numbers 1 through 7. If you divide out a fraction with the denominator 7, something odd appears. The result is a repeating decimal (that is, it has no end, but the same numbers keep coming up in the same order). Thus 1/7 is 0.142857142857142857 . . ., the repeating sequence is 142857; no matter how long you go on dividing, you’ll just get those same six numbers coming up. That is not odd, but here is what is: The decimal equivalent of 2/7 is also a repeating sequence: 285714. And so on with other fractions of 7: 3/7 = 428571; 4/7 = 571428; 5/7 = 714285; 6/7 = 857142. Do you spot what’s odd? All of those repeating sequences consist of the same six numbers in the same order, only beginning at a different place in the sequence. Seven is an odd number. In several senses.
NOTE: Several of these facts about seven are from Zero to Lazy Eight: The Romance Numbers, by Alexander Humez, Nicholas Humez, and Joseph Maguire (New York: Simon & Schuster, 1993), a book full of number lore and other ibonis (interesting bits of needless information).